The Inelastic Input Energy Spectra for Main Shock–Aftershock Sequences

Zhai, Changhai; Ji, Duofa; Wang, Wen; Lei, Weidong; Xie, Lili; Gong, Maoguo

doi:10.1193/121315eqs182m

Cited by 31 publications

(13 citation statements)

References 37 publications

(54 reference statements)

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“…Especially, nonlinear single degree of freedom (SDOF) systems subjected to MSAS sequences were used in Refs. [1][2][3][4][5][6] and both global and local damage indices accounting for energy dissipation [7] were found to be highly sensitive in the MSAS seismic records. Contrarily, no sound influence was corroborated on deformations-based indices including the maximum and residual displacement as well as displacement ductility.…”

Section: Introductionmentioning

confidence: 99%

Seismic Fragility of Rc Structures Under Mainshock-Aftershock Sequences Recorded on Soft Soil Conditions

Ji¹,

Katsanos²

2019

Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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Past earthquake episodes of moderate-to-high magnitude have shown that strong mainshock trigger usually strong aftershocks forming, in such a way, the so-called mainshock-aftershock (MSAS) sequences. The latter can normally induce higher seismic losses to structures and infrastructures compared to the single mainshock event. High vulnerability has been also detected for structural systems being subjected to the soft soil earthquake strong ground motions due to the soft soils-driven amplification in structural demand. Along these lines, this study investigates the seismic fragility of an existing reinforced concrete (rc) structure subjected to MSAS sequences recorded on soft soil profiles. To this end, a preliminary selection of 28 and 52 soft-soil mainshocks and aftershocks strong GMs respectively served the basis to generate 36 artificial earthquake sequences. The latter were made of six mainshocks and six aftershocks seismic motions that are representative of the initially formed sets of records in terms of the predominant period, T g , and the strong ground motion duration. An existing seven-story rc building located in Van Nuys, California, was modelled by using the OpenSees finite element code. The measured response of the building during the Northridge (1994) earthquake episode was used to validate the finite element model developed herein. Nonlinear time history analysis was performed and the soft-soil MSAS-induced structural response (i.e., roof drift, maximum interstory drift ratio and maximum residual interstory drift ratio) was comparatively assessed with the response induced by MSAS sequences recorded on firm soil conditions. Fragility analysis was also conducted and the relevant fragility curves were estimated accounting for varying intensity of the aftershocks. Based on the results derived herein, the firm-soil MSAS led to higher structural collapse capacity compared to the one that was calculated by using the soft-soil MSAS, the latter being more profound when the building was subjected to aftershocks with increased intensity.

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Section: Introductionmentioning

confidence: 99%

Seismic Fragility of Rc Structures Under Mainshock-Aftershock Sequences Recorded on Soft Soil Conditions

Ji¹,

Katsanos²

2019

Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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“…It was reported that the ASs could lead to a significant increase in structural inelastic deformation and energy dissipation. After that, various structural performance indicators, e.g., peak displacement response [5][6][7], behavior factor [8,9], ductility demand [8,[10][11][12][13], input energy [14], damage index [15], and collapse capacity [16], have been adopted to examine the AS effect by subjecting SDOF systems to a suite of real [11,12] or artificial [8][9][10][11]15,16] MS-AS sequences. Recently, multiple degree of free dom systems (MDOFs) have been used to investigate the structural damage caused by MS-AS sequences; the studied structures include steel frames [17] bare and infilled reinforced concrete frames [18][19][20], wood structures [21], equipped structures [22], bridges [23] and other kind of structure [24].…”

Section: Introductionmentioning

confidence: 99%

Identifying Optimal Intensity Measures for Predicting Damage Potential of Mainshock–Aftershock Sequences

Zhou

Lü

2020

Applied Sciences

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Large earthquakes are followed by a sequence of aftershocks. Therefore, a reasonable prediction of damage potential caused by mainshock (MS)–aftershock (AS) sequences is important in seismic risk assessment. This paper comprehensively examines the interdependence between earthquake intensity measures (IMs) and structural damage under MS–AS sequences to identify optimal IMs for predicting the MS–AS damage potential. To do this, four categories of IMs are considered to represent the characteristics of a specific MS–AS sequence, including mainshock IMs, aftershock IMs (i.e., IMMS and IMAS, respectively), and two newly proposed IMs through taking an entire MS–AS sequence as one nominal ground motion (i.e., IM1MS–AS), or determining the ratio of IMAS to IMMS (i.e., IM2MS–AS), respectively. The single-degree-of-freedom systems with varying hysteretic behaviors are subjected to 662 real MS–AS sequences to estimate structural damage in terms the Park–Ang damage index. The intensities in terms of IMMS, IMAS, and IM1MS–AS are correlated with the accumulative damage of structures (i.e., DI1MS–AS). Moreover, the ratio (i.e., DI2MS–AS) of the AS-induced damage increment to the MS-induced damage is related to IM2MS–AS. The results show that IM2MS–AS exhibits significantly better performance than IMMS, IMAS, and IM1MS–AS for predicting the MS–AS damage potential, due to its high interdependence with DI2MS–AS. Among the considered 22 classic IMs, Arias intensity, root-square velocity, and peak ground displacement are respectively the optimal acceleration-, velocity-, and displacement-related IMs to formulate IM2MS–AS. Finally, two empirical equations are proposed to predict the correlations between IM2MS–AS and DI2MS–AS in the entire structural period range.

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“…Ruiz‐García, [ 2 ] Goda, [ 3 ] and Goda et al [ 4 ] studied the differences in characteristics between a mainshock and major aftershock records, providing useful insights into the MSAS records selection or generation. The response spectra of MSAS sequences were proposed for the performance evaluation [ 5–9 ] and seismic design [ 10–14 ] after considering the effects of aftershocks. The influence of MSAS sequences on the seismic response of buildings, mainly including steel frames [ 15–18 ] and reinforced concrete (RC) frames, [ 19–21 ] was also investigated with recorded or artificial MSAS sequences.…”

Section: Introductionmentioning

confidence: 99%

Vulnerability assessment of a high‐rise building subjected to mainshock–aftershock sequences

Wang

Zhai

2020

Structural Design Tall Build

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Summary Strong aftershocks have the potential to further aggravate the damage state of structures, and much less attention has been given to the seismic vulnerability of high‐rise buildings than that of low‐ to medium‐rise buildings. This study assesses the seismic vulnerability of a 32‐storey frame–core tube building by performing the incremental dynamic analysis on the material‐based three‐dimensional numerical model. A storey damage model based on the material damage is developed using the weighted average method. Eighteen recorded mainshock–aftershock sequences, whose mainshock records match the target spectrum, are selected. The results indicate that the developed stroey damage model can effectively reflect the additional damage induced by aftershocks. Strong aftershocks have high potential to change the location of weak storeys. Notably, shifts of weak storeys are observed in more than 30% of aftershocks with relative spectral acceleration of 0.8. As the mainshock‐induced damage state becomes more severe, the mainshock‐damaged building becomes increasingly fragile to the aftershock excitation and more sensitive to aftershock intensities. The probability of exceeding severe damage state increases from 35.3% to 62.1% due to the effects of strong aftershocks. The results in this study can provide supports to the seismic resilience assessment of this high‐rise building.

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The Inelastic Input Energy Spectra for Main Shock–Aftershock Sequences

Cited by 31 publications

References 37 publications

Seismic Fragility of Rc Structures Under Mainshock-Aftershock Sequences Recorded on Soft Soil Conditions

Seismic Fragility of Rc Structures Under Mainshock-Aftershock Sequences Recorded on Soft Soil Conditions

Identifying Optimal Intensity Measures for Predicting Damage Potential of Mainshock–Aftershock Sequences

Vulnerability assessment of a high‐rise building subjected to mainshock–aftershock sequences

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